The development of high performance polyolefin resin depends on increasing improvement of the olefin polymerization catalyst. U.S. Pat. No. 4,298,718 and U.S. Pat. No. 4,495,338 relate to use active magnesium halide as a support of Ziegler-Natta catalyst for the first time, in which the catalyst formed by reaction of the support and titanium tetrachloride shows high activity in propylene polymerization, but has poor stereoselectivity. Subsequently, researchers are striving to improve the performance of the catalyst. GB Patent No. 2,111,066 discloses a high isotacticity polypropylene can be obtained by adding an electron donor (alkoxyl silicon compound) into a solid titanium catalyst during olefin polymerization, which is formed by contacting a liquid hydrocarbon solution of the magnesium compound with the titanium compound in the liquid state and meanwhile adding another electron donor (e.g. phthalate). EP Patent No. 0361,494 discloses a solid catalyst comprising active magnesium halide, titanium compound having at least one Ti-halide bond supported thereon and organic di- or poly-ether, such as the catalyst obtained by using a 1,3-diether as electron-donor compound. Under polymerization, such catalyst system can obtain high isotacticity polypropylene without adding external electron donor and having higher activity. Chinese Patent No. 1,143,651A further improves internal electron donor and/or external electron donor of such catalysts, in which 2-position carbon atoms of 1,3-diether are used to form a special monocyclic or polycyclic structure with organic groups containing two or three unsaturated bonds, namely, cyclic polyene-1,3-diether. The activity and stereoselectivity of such catalysts have been improved. Chinese Patent No. 1,306,544 describes that succinate is used as the internal electron donor to prepare a catalyst, which shows higher activity and stereoselectivity during catalyzing propylene polymerization and produces polypropylene with wider molecular weight distribution (MWD).
As stated in the above representative catalytic polymerization systems, electron donor has various effects on activity and stereoselectivity of the catalyst, and polymer performance, and has a crucial role to the tacticity of polypropylene. Therefore, the development of the polyolefin catalyst is to optimize the existing electron donors and develop novel electron donors. Most of the electron donors currently reported are compounds containing P, N and O, such as carboxylic ether, ether, organophosphine, amine, silicon compound, etc, which belong to several main categories of monoesters, diesters (including succinates, alcohol esters) and diethers, etc. It has been found during investigation that sulfonyl-containing compound used as the electron donor has special reactive performances with titanium compound and magnesium compound, and the resulting catalyst shows higher activity and stereoselectivity during catalyzing olefin polymerization.